You beat me to it, I was about to say you if you can keep the battery pack part of the rear frame then the issue of cable movement/twist is negated.

Each design has its merits. Your current design allows for the tilt of the whole trike so you may gain something from the CoG change as long as you can eliminate or reduce bump steer when at full tilt.

True. It's not a good example of what I was trying to explain either, so I've taken the liberty of copying one of the earlier pictures you posted and have tried to edit it to get across the idea I have:

Where I've drawn in red would be the "rear" frame that the motor, diff, rear suspension etc mount to. The "front" frame would be all the remaining green frame of your existing design and it would attach to the new "rear" frame at two points, one bearing in the front and one bearing in the rear. This would allow the green frame to pivot around the red frame.

I hope this makes sense.

Last edited by TooQik on Sun, 24 Jan 2016, 09:42, edited 1 time in total.

EV2Go wrote:The battery cables go from the main pack at the front to the controller at the back. No problems there but when you try route the cable from the controller to the motor is where all hell breaks loose.

What about passing the cables from the controller to the motor through the bearing centre on the rear bearing? There would be minimal movement in this scenario and you would just need to ensure the cables were routed in the rear frame so as not to foul on the suspension components.

EV2Go wrote:If suspension was applied to diff, it would take the path of least resistance and try turn at the outside bearings.

Isn't that what you're trying to achieve though? If the trike hits a bump with one wheel that side's suspension moves up, this in turn pushes on the rear frame which can pivot independantly of the front frame via the outside bearings. This would mean that the bump is absorbed without changing the tilt of the front frame / rider.

Last edited by TooQik on Mon, 25 Jan 2016, 06:08, edited 1 time in total.

EV2GO I remember you discussing the design of this back diff tilt( a couple of years ago) and disagreeing with your original plan, but this, your latest plan will work and is as simple as it possibly could be. As you say if the suspension is air, then it allows tilt. If the movement in the shocks (springs?) is too short then just move the anchor point closer to the centre of the diff.
Just one thing to watch is the batteries centre of gravity needs to be inline with the tit axis otherwise it will want to fall to one side all the time unless the centre of gravity is lower than the tilt axis, then it will resist tilting.

I am referring to the design with the bar going over the diff with the whats linkage.

Last edited by GRMarks on Tue, 26 Jan 2016, 12:16, edited 1 time in total.

The leaf spring would work but the air suspension idea would be adjustable and you could have a restrictor in the line that joins the 2 together to give some resistance for tilt. In other words highly tuneable making it possible to get it just right.

EV2Go wrote: Imagine this blue bar was the shock (or even rigidly mounted) which effectively stops the diff from rotating freely on the front and rear bearings.

If there was a second set of free moving bearings sitting just outside the inside bearing, the kinetic energy from the road bump would see the shock as a decent form of resistance, and say that's too hard for me to move and treat that whole unit like it was locked up (just like a solid bar would do).

That bump energy would then see the freely rotating outside bearings just outside those inside bearings and say hey it's much easier if I just tilt the diff from this point instead.

Hence the problem you can't have both an actively returning suspension and tilt, it has to be one or the other.

The other alternative is to not restrict the bearings (i.e. no shock) and that would allow the tilt and the diff movement but no active pressure for the wheel return.

you need to be careful where you mount your shocks on a nine inch, I broke one in half on rough road it cracked on the weld from Banjo to axle tube and broke in half. Nothing a big gusset did not fix.